I just purchased an MC7C with an 8V92 engine and I am new to buses after owning a Fleetwood Discovery with a Cummins 5.9. The first thing I did is I went to ABC in Garden Grove CA to purchase oil and filters. They didnít seem to know much about this engine which I thought was a bit surprising as I thought they were quite common. They didnít seem to know how much oil it takes and said it could be between 7 and 10 gallons. They also didnít know which oil filter to use. Another customer called Detroit Diesel while we were standing at the counter and asked them and I got a filter.

I also asked which oil they recommend and they gave me 76 T5X 15W-40. I changed the oil and filters. Since then I have read thru several older issues of Mikeís Bus Conversions magazines and have seen two references so far which say not to use multi viscosity oil in these engines. Is ABC a reputable company and they know something the readers of Bus Conversions donít know or am I in the process of ruining my engine? Why is multi viscosity oil not recommended for southern CA?

Whatever you do, DUMP that multi-weight oil IMMEDIATELY. Someone more knowledgeable than me has posted on here the single weight oil is the only oil that will prevent fast and untimely wear of critical internal parts...

Hello Gary,First off welcome to the BEST source of information available about bus conversions! Now about ABC they are a repitable company, but keep in mind their main line of buses is VanHool and most off those are Cummins equipped! †So not surprisingly most of their help probably knows less about a 2 stroke Detroit (any Detroit designed prior the the 50-60 series engines, not limited too but most common among us are the 6-71, 6V71, 8V71, 6V92, & 8V92 there are others but these are the ones you'll hear mostly about here) than you do. Now always use a straight 40W oil with the lowest possible ash content as pointed out by Niles! †For an excellant reading on 2 strokes and oil go to www.tejascoach.com/tejasoil.html(cut & paste as I don't know how to make it a link or short cut! LOL!) It's hard to find anyone in the BIG shops these days who know about our beloved 2 strokes! †FWIW.BK †

[i]I fixed it for you BK so that you just have to click on it. No cut and paste required.Richard[/i]

Most younger people know very little about DD two stroke engines and the old GM manual trans.

The engines use CF-2 oil which I found in Home Depot of all places. It is Rotella T-40 as I remember. Look on the label. If it says CF-2 ok. If it says CF-4, not ok. Multi viscosity is not recommended for DD 2-stroke under any conditions or anywhere.

The 4 speed trans use 50W mineral oil. I use aircraft 50W engine break in oil in my trans which has no additives and is called for in the manual.

Oh yeah I forgot about the how much does it hold rule? You'll have to change it and keep watching it as you add until you hit the Magic mark on your dipstick! I've seen 2 iof the same yr, model, & engine buses hold different amounts!!! WHY? Different oil pans, different oil cooler set ups, and etc. So it's best to check it out the first time and jot it down somewhere for future use. (I usually write it on the inside of the engine compartment door with a permant marker so it's always visable to "whoever changes the oil" just incase it's not me! BK †

After installing new oil, of the proper amount for your engine, wait at least one hour in order to get a correct reading on your dipstick. That way it gives it time for the oil to get to the pan.When I first bought my bus I did not know that. I stopped to fuel up, checked the oil and found it one gallon low, I added one gallon of oil. Later on I was cruising along and noticed the oil pressure was real low, I thought I must have a leak. Not at all, it was over the full mark by a lot. Not good. I do not understand why this is so, but I know it is not good. So I am very picky during the dipstick check!If my assumptions are not correct, please let me know.

Gary, I did some digging around on this subject and here is what I found out.

One way the oil makers cause oil to have a multiviscosity behavior is to make the oil molecules ovoid in shape, so they slide over each other easier when cold. Straight weight oil molecules are round, by comparison.

To see where this plays a role, consider the port area, where the intake air enters the cylinders. The rings have to pass over these ports, and even though it is very slight, the rings expand where they are unsupported. This means that oil film protection can fail to keep metal parts far enough apart as the rings reach the end of the ports.

With the round molecules, the minimum oil film thickness is enough to keep the rings from hitting the edge of the ports; just as important, the round molecules are a lot harder to shear than the ovoid ones. The oil in these engines seems to pick up soot faster than four stroke engines, as well. In addition, if there is any tiny abrasive in the oil, it's much easier for it to get caught between rings and liner and cause wear.

Many years ago, 30 weight was the recommended oil, but it's always 40 weight, now, at normal temperatures. I'm sure that the oil molecule is larger, too.

Four stroke engines have smooth liner bores with no openings that the rings have to pass over, so their problems are entirely different. So, the formulation is different.

WOW! I can't believe the number of responses I received in less than 12 hours. I will take your advice and dump the multi-viscosity oil. So far, I have only run the engine for 15 minutes about 3 times since putting it in. Now for the next question, should I go back to ABC with printouts of this thread and ask for a refund, or just take my business elsewhere as they obviously no nothing about Detroit Diesel engines?

Hatt:I don't think ABC will refund your money on used oil, even though they said it is the right oil. Be glad you found this board and all the knowledge that is here. For what this board has saved you the money you lost on the wrong oil is cheap. I also found out about the correct oil to use in my 8V92 MCI 7 from this board.EDMCI 7

I run the wrong oil in my 8V92 for several months and several thousand miles before I discovered that it was supposed to be straight 40W. (that was before the days of the INTERNET and bus boards). I do not believe it did any damage to the engine, since I put well over 100,000 miles on it later, but it did significantly reduce the oil consumption when I changed to straight 40.Richard

Hatt:I don't think ABC will refund your money on used oil, even though they said it is the right oil.† Be glad you found this board and all the knowledge that is here.† For what this board has saved you the money you lost on the wrong oil is cheap.† I also found out about the correct oil to use in my 8V92 MCI 7 from this board.EDMCI 7

« Last Edit: January 24, 2007, 10:36:37 AM by DrivingMissLazy »

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Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming: WOO HOO, what a ride

First, print out this link. It's Detroit Diesel's official publication regarding lubricating oils for their engines. Read it thoroughly, you'll see in Section 2.2 where they talk about the lubricant requirements for the two-stroke series, which is what you've got.

Now, armed with this info direct from the horses' mouth, make an appointment to see the service manager at ABC. Tell him that you believe a mistake has been made, and you'd like to talk to him about it in person. Be polite and professional, but don't get into a discussion of the problem on the phone. Just make the appointment.

When you go in to see him, take your receipt for the oil change (make sure you highlight the oil they used), and your copy of the Detroit publication you printed out. Point out to him what Detroit requires in your engine, and what ABC failed to use when they did the oil change, based on what your receipt indicates. Ask him to rectify the situation, and see what his response is. If you're polite and professional, chances are very good that he'll correct the situation by having you bring your coach back in, and they'll replace the multi-weight with the correct 40wt, at no cost to you.

ABC is a reputable company, but it's pretty obvious that somebody screwed up, and they should stand behind their mistake and correct it.

If not, then ask to see the General Manager, and repeat the process. Be sure to let him know that you'll start spreading the word via the Internet that ABC doesn't take care of their customers when they make a mistake. Don't mention the Internet with the Service Manager, just the GM.

IF the GM won't work with you, a quick phone call to ABC's headquarters will do wonders. . . Clancy Cornell has worked long and hard to build ABC's reputation as a good company to work with, so you will get their attention.